1. Field of the Invention
The present invention relates to a lightsensitive material package. More particularly, the present invention relates to a lightsensitive material package in which a color photographic lightsensitive material having an emulsion of high aspect ratio is arranged in a common gas phase atmosphere and sealed with recycled plastic material members constituted of reclaimed resins, the above reclaimed resins obtained through remelting of, for example, plastic material members made of thermoplastic resins.
2. Description of the Related Art
Reclaimed resins, as plastic material members, are used in, for example, a body of lens-fitted packaging unit and a spool or core of 35 mm patrone, and further used in, other than those accommodated together with a lightsensitive material, a photographic film case and other accommodating items. Further description will be made with reference to a lightsensitive material packaging unit including a built-in color negative photographic lightsensitive material and furnished with an exposure function (known as a lens-fitted film), now widespread for its convenience.
Generally, the cartridge of lens-fitted lightsensitive material packaging unit is produced by molding a high impact polystyrene resin comprising a polystyrene resin (hereinafter referred to as “PS resin”) to which a butadiene rubber polymerization has been carried out to thereby impart impact resistance, which high impact PS resin contains carbon black for light shielding and various additives for moldability enhancement. This cartridge of lens-fitted lightsensitive material packaging unit, because of its built-in photographic film, is constituted of resins selected with the care that there should be no fogging or abnormal sensitivity attributed to gases released from impurities or resin ingredients contained therein.
Each lens-fitted lightsensitive material packaging unit, after photographing, is sent to a laboratory, where the film having undergone photographing is taken out, developed and fixed on a photographic paper. The packaging unit from which the photographic film has been removed, for the purpose of environmental protection and resource saving, is collected, converted to reclaimed resins through steps such as disassembly, classification, crushing and melting, and reutilized as a molding material for the cartridge of lens-fitted lightsensitive material packaging unit or the like.
With respect to reclaimed resins, the use thereof in parts brought into contact with the photographic film has been restricted because of the reclamation from products collected on the market, in particular because of the concern about any increase of the occurrence of photographically harmful substances attributed to resin pyrolysis by an increase of heat history and also the concern about the inclusion of substances harmful to photographic film as described in Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-) 5-165154.
With respect to harmful substances from thermoplastic resins which have adverse effects on photographic lightsensitive materials, it is presumed that, as described in JP-A's-6-130565 and 6-67356, aldehydes, ketones, free sulfur, cyanide and other compounds resulting from resin pyrolysis are gasified and adsorbed on film surface to thereby denature the silver halides of the film with the result that the photographic properties are changed.
The generation of harmful substances from such resins would be attributable to carbon black, various additives and rubber components and, with respect to reclaimed resins, to impurities adhered thereto on the market.
As a result of practical fogging tests of a high-speed lightsensitive material, i.e., a lightsensitive material of high silver content accommodated in moldings of the same configuration but constituted of a reclaimed resin on the one hand and a virgin resin on the other hand, it has been found that no adverse effect is exerted in the use of a virgin resin while an adverse effect disenabling any practical use occurs in the use of a reclaimed resin.
With respect to gases which are harmful to photographic films, it is described in JP-A-6-130565 that, the greater the heat history frequency at molding or extrusion in the presence of an antioxidant, the greater the evaporation of impurities, so that the amount of antioxidant is less in the reclaimed resin than in the virgin resin. This would reflect that, with respect to the reclaimed resin, the heat history is increased to thereby reduce the amount of antioxidant and cause new photographically harmful gases to occur from the PS resin containing rubber components. Further, it is described in JP-A-6-67356 that harmful substances are suppressed by the addition of an antioxidant or the like. However, in the use of reclaimed resin, the above component reduction occurs with the result that the effect exerted by the virgin resin is diminished.
On the other hand, a speed increase of lightsensitive material has been and is demanded for enhancing the quality of image obtained by the lens-fitted lightsensitive material packaging unit. Various researches for improvement have been carried out in order to attain a photographic speed increase. With respect to the use of tabular emulsion, U.S. Pat. No. 4,433,048 discloses a particular process for producing tabular silver halide grains and a method of using the same. It is known that the configuration of tabular grains is advantageous in, for example, improvement as to the relationship of photographic speed/graininess, sharpness enhancement attributed to specific optical characteristics of tabular grains and increase of covering power. Such a technology that high speed, enhanced graininess and sharpness and excellent pressure resistance can simultaneously be attained by the use of tabular grains of 5 or more aspect ratio having dislocation lines in a lightsensitive material of 320 or more ISO speed in an emulsion layer most remote from its support is disclosed in JP-A-5-341459.
However, the problem that the use of tabular silver halide grains of 8 or more aspect ratio in a high-speed layer for the purpose of photographic speed increase and image quality enhancement invites fogging of lightsensitive material, especially an increase of fogging by prolonged storage, has surfaced. Attaining an improvement on this problem is now an important task.
Moreover, with respect to the deterioration of photographic properties by harmful substances in the lens-fitted lightsensitive material packaging unit which includes the above reclaimed resin, the greater the speed of lightsensitive material, the greater the influence of harmful substances on the lightsensitive material. Therefore, in particular, the use of reclaimed resin has been restricted in the lens-fitted lightsensitive material packaging unit wherein a high-speed lightsensitive material is accommodated.